Moving beam and field of view readers with dichroic filter

摘要

An optical reader for reading indicia such as bar codes comprises a first and second light source for generating first and second laser beams. The respective laser sources generate light at different wavelengths and a dichroic filter is provided to allow either source to be used without parallax effects. The laser scanner beam can be used to aim the reader when carrying out field of view reading. The optical reader is further provided with a band-pass filter shaped to match the wave-front of light generated at a given location incident on the filter to reduce the band-pass bandwidth and hence the ambient noise. The shaped band-pass filter can be incorporated in the optical reader dichroic filter arrangement.